The present invention is directed to electrical winding structures that may be employed in electromagnetic devices such as, by way of example and not by way of limitation, transformers, relays, solenoids and similar devices.
Prior art electromagnetic devices employ discrete structures for each winding stratum about a central member. The central member may be embodied in a ferrous core, another type of magnetic core, an air core or a mandrel used solely to effect a winding operation. For example, if one wished to provide a device with a primary winding and a secondary winding, each of the primary and secondary windings would be a discrete winding structure unconnected with the other. Such an arrangement is not a problem in a simple winding structure. However, it may be advantageous to employ a more complex winding structure that requires interleaving or otherwise alternating segments of a primary winding and a secondary winding. The effect may result in an A-B-A-B arrangement of windings where A-layers may be a primary winding and B-layers may be a secondary winding. Providing electrical access, such as by connecting termination structures or leads to alternating layers situated in the interior of the winding structure is problematic. The problems associated with such a structure generally result in more difficult manufacture, manual assembly and less stringent operating limits. Such characteristics generally result in a more expensive looser-tolerance product. Individual electrical leads provided for each layer of a respective winding (primary winding or secondary winding) at each interleaved or alternated stratum present can present a virtual “forest” of multiple leads for effecting proper connection of the unit within a host device. Such multiple connection leads present their own problems and attendant costs in effecting assembly of a device employing such a multi-lead electromagnetic unit.
There is a need for a method and structure for assembling electrical windings about a central member for an electromagnetic device that does not require multiple leads for terminating with discrete layers of respective windings located within the interior of the device.